W89C982 Ver la hoja de datos (PDF) - Winbond

Número de pieza

componentes Descripción

Lista de partido

W89C982

INTEGRATED MULTIPLE REPEATER II

Winbond 

Preliminary W89C982AF

fail state, the IMPR II will not transmit any signal (packets or link pulses) on the TP port and the first

input packet will not be retransmitted. The IMPR II will transmit link test pulses to any TP port after

the transmitter of the TP port has been inactive for more than 16 mS after the TP port enters link

good state. The link test function of the TP port is user-programmable using the management

functions of the IMPR II. The TP port is forced into link good status if the link test function is disabled.

The link test function is enabled by default each time the IMPR II is reset.

Automatic Polarity Reversal Function

The automatic polarity reversal function checks the polarity of the input data packets or link pulses.

The polarity of the TP port will be set to negative when the polarity of the first input packet or the first

three consecutive link pulses following reset or following entry of the TP port into link fail state are

detected to be negative. Once the polarity of the TP port is set to negative, all consequent input

packets will be retransmitted with data that are inverted with respect to the input packet after the TP

port enters link good state. If the polarity of the TP port is not set to negative, all input packets will be

retransmitted without any modification of the data polarity. Once the polarity of the TP port is

determined, the polarity of this port will not be updated until the IMPR II is either reset or re-enters link

fail state, regardless of whether the automatic polarity reversal function is disabled or enabled. The

automatic polarity reversal function is user-programmable using the management functions of the

IMPR II and is enabled by default each time the IMPR II is reset. The default status of polarity is

"correct" when the IMPR II is in reset state.

Port Partition/Reconnection Logic

The port partition/reconnection logic implements the segment partitioning algorithm and the segment

reconnection algorithm. These algorithms are defined by IEEE specifications and are used to protect

the network from malfunctioning segments. There are nine partition/reconnection machines in an

IMPR II. Each port partition reconnection machine controls an individual network port.

A network port will be partitioned by the IMPR II when either of the following conditions is detected:

(1) A collision condition exists continuously for a period of up to 1024 bit times.

(2) Thirty-two consecutive collisions occur.

A collision condition is defined as more than two network ports attempting to transmit simultaneously

or as a receive collision from the AUI.

The IMPR II can reconnect a partitioned network port using algorithms selected by programming the

management logic. The following are the two reconnection algorithms:

(1) Standard reconnection algorithm:

A partitioned network port will be reconnected if a data packet longer than 512 bit times is

retransmitted to or received from that port without collision.

(2) Alternative reconnection algorithm:

A partitioned network port will be reconnected if a data packet longer than 512 bit times is

retransmitted to that port without collision.

The reconnection algorithms for all the TP ports and the AUI port are programmed individually;

however, all the TP ports use the same algorithm. The standard algorithm is selected by default each

time the IMPR II is reset.

Port Status Direct Report Function

Publication Release Date: November 1996

-9-

Revision A1

Share Link: